1. Field of the Invention
The present invention relates to a droplet discharge head and a droplet discharging unit incorporating the same, which may be included in a printer. Each of wall surfaces of a liquid reservoir and of a nozzle may be formed in a linear configuration as seen in a cross-sectional view or each of the wall surfaces may have a width narrowing toward an orifice so that, at a connecting portion of the liquid reservoir and the nozzle, the nozzle is wider than the liquid reservoir. With this configuration, the likelihood of malfunctions caused by ingress of air bubbles, dust or other foreign matter into the liquid reservoir may be reduced.
2. Description of the Related Art
Inkjet print heads discharge ink stored in an ink reservoir when a driving element changes the pressure in the ink reservoir. The driving element may include a piezoelectric element or a heater element.
A print head with a heater element as a driving element may be fabricated in the following manner. First, a drive circuit of the heater element, a heater element and other components may be sequentially mounted on a semiconductor substrate. Partition walls of ink reservoirs and of an ink channel may then be mounted on the semiconductor substrate by, for example, photolithography using photosensitive epoxy resin. A nozzle sheet, which is a sheet-like component on which nozzles are arranged, is provided on the semiconductor substrate. The ink reservoirs, the ink channel, the nozzles and other components may alternatively be integrated with one another.
Japanese Unexamined Patent Application Publication (JP-A) No. 5-77437 discloses, for example, a print head with a system for preventing nozzle clogging.
Printers suffer from a problem that defective printing may be caused by ingress of air bubbles, dust or other foreign matter into an ink reservoir. Recent printers have small nozzles for high quality and high resolution printing. Such fine nozzles may be a cause of defective printing.
In order to address this problem, a method disclosed in No. JP-A-5-77437 may be employed to periodically check defective printing. It is necessary, however, to frequently checking defective printing and the defective printing may not completely be eliminated. Defective printing may not be checked while a paper sheet is under going printing. Consequently, such a related art process is still impractical.